The present invention relates to a new and improved construction of a calender having displaceable bearing parts.
In its more particular aspects, the present invention relates to a new and improved construction of a calender having displaceable bearing parts and intermediate rolls which are arranged between an uppermost roll and a lowermost roll and supported at their respective axles. The displaceable bearing parts are secured at one side of nip-=relieving devices having an other side which is upported at an elevationally displaceable support member which is suspended at a stand. A slide guide is provided for elevationally displacing the bearing parts in the stand by means of bearing part portions which are adapted to the slide guide.
Such calenders are used, for example, in the paper industry for processing or refining paper webs. The calenders comprise a number of intermediate rolls which are arranged between an uppermost roll and a lowermost roll and can be pressed together by these uppermost and lowermost rolls. As a result, a pressure builds up between the rolls of the calender. Efforts are made to have, between the individual rolls, gaps, the so-called nips, possessing as far as possible the same clearance across the entire width of the nip. As is well known, this is adversely influenced by so-called overhanging weights which act upon each roll on both sides thereof in the downward direction. It is known to arrange nip relieving devices between the roll and the stand of the calender in order to compensate for the overhanging weights. In a known calender which, for example, is known from the European Patent Application No. 86116695.7 (W. G. Stotz), published Aug. 5, 1987 (Publication No. 0,230,563) and cognate with U.S. Pat. No. 4,736,678, granted Apr. 12, 1988, the nip relieving devices are hydraulic cylinder-and-piston motors by means of which a force is adjustable, which force acts against the force of the overhanging weights. The intermediate rolls are thereby mounted in bearing parts which are elevationally displaceable along a slide guide. Since in this calender the diameter of the individual rolls varies owing to wear of the surface thereof, the rolls are at times in a different elevational position. Such changes must be pursued also by the nip relieving device. Normally, the support members for the nip relieving devices are elevationally displaceably arranged at the stand. The main problem of the hitherto existing constructions results from the limited space which is available for the nip relieving devices between the individual rolls to be supported.